How do you long divide n^2-11n-26 div n+2?

1 Answer
Nov 10, 2015

(n^2-11n-26) div (n+2) = (n-13)
(see explanation for details of long polynomial division)

Explanation:

Set up as if doing a standard long division
{: (,,"-----","-----","-----"), (n+2,")",n^2,-11n,-26) :}

The leading term of the divisor color(green)(n) divides into the leading term of the dividend color(blue)(n^2), color(red)(n) times

{: (,,color(red)(n),,), (,,"-----","-----","-----"), (color(green)(n)+2,")",color(blue)(n^2),-11n,-26) :}

Multiply the divisor color(green)(n+2) by the term just written in the quotient (color(red)(n)) giving a product of color(cyan)(n^2+2n)
and subtract this product from the dividend giving a difference of color(blue)(-13n) and "bring down the next term, color(orange)(-26)
{: (,,color(red)(n),,), (,,"-----","-----","-----"), (color(green)(n+2),")",n^2,-11n,-26), (,,color(cyan)(n^2),color(cyan)(+2n),), (,,"-----","-----",), (,,,color(blue)(-13n),color(orange)(-26)) :}

Repeat this process to get:

{: (,,n,-13,), (,,"-----","-----","-----"), (n+2,")",n^2,-11n,-26), (,,n^2,+2n,), (,,"-----","-----",), (,,,-13n,-26), (,,,-13n,-26), (,,,"-----","-----"), (,,,,0) :}